Small mixer impeller design is not tailored for granulation because impellers are intended for a wide range of processes. The aim of this research was to evaluate the performances of several impellers to provide guida...Small mixer impeller design is not tailored for granulation because impellers are intended for a wide range of processes. The aim of this research was to evaluate the performances of several impellers to provide guidance on the selection and design for the purposes of granulation. Lactose granules were produced using wet granulation with water as a binder. A Kenwood KM070 mixer was used as a standard apparatus and five impeller designs with different shapes and surface areas were used. The efficacy of granulate for- mation was measured by adding an optically sensitive tracer to determine variations in active ingredient content across random samples of granules from the same size classes. It was found that impeller design influenced the homogeneity of the granules and therefore can affect final product performance. The vari- ation in active ingredient content across granules of differing size was also investigated. The results show that small granules were more potent than larger granules,展开更多
Some commonly used constructions and their design principles of centrifugal pump impeller with super low specific speed are introduced. The internal flow related to pump performance is analysed primarily.
Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simpli...Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression（SVR） metamodel is combined with the Monte Carlo simulation（MCS） method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.展开更多
An impeller is the most important component affecting the performance of centrifugal fans. The flow in the impeller is very complicated, and the 3\|D viscous flow is difficult to simulate numerically. This paper prese...An impeller is the most important component affecting the performance of centrifugal fans. The flow in the impeller is very complicated, and the 3\|D viscous flow is difficult to simulate numerically. This paper presents a numerical method for simulating the flow in practical commercial impellers. The predictions are compared with experimentally measured fan performance results. The predicted total pressure and efficiency for two fan models, whose optimum designs were determined by this method, agree well with the measured data for the design flow rate. The results show that the aerodynamic and noise levels for these two models are excellent. The paper also presents several new ideas about the shape of the front plate and the blade flow pattern to improve the flow in an impeller channel. The practical simulation methodology and results developed here will be very useful to the fan industry in the future.展开更多
Wet granulation is one of the most important agglomeration processes,and high-shear granulation(HSG)one of the most employed technologies in the pharmaceutical industry.The most critical process parameters of HSG are ...Wet granulation is one of the most important agglomeration processes,and high-shear granulation(HSG)one of the most employed technologies in the pharmaceutical industry.The most critical process parameters of HSG are discussed in this work.The main concern in scaling up the wet granulation process is the differences between scales,which prevent the particles from having the same experience across all scales.The scale-up of wet granulation processes is commonly divided into two categories:engineering and attribute-based methods.An engineering-based scale-up approach is a strategy based on dimensional analysis and an attribute-based supported on the principles of“equifinality”,where process variables are adjusted to obtain equivalent granule attributes.This work presents the effect of different HSG process parameters on the scale-up,as well as the use of process analytical tools(PAT)and modelling strategies.The aim is to review applied scale-up approaches in HSG and discuss benefits and limitations.It is proven why the scale-up for oral solid pharmaceutical products is still considered a hot topic and a very challenging task for development and engineering teams.展开更多
文摘Small mixer impeller design is not tailored for granulation because impellers are intended for a wide range of processes. The aim of this research was to evaluate the performances of several impellers to provide guidance on the selection and design for the purposes of granulation. Lactose granules were produced using wet granulation with water as a binder. A Kenwood KM070 mixer was used as a standard apparatus and five impeller designs with different shapes and surface areas were used. The efficacy of granulate for- mation was measured by adding an optically sensitive tracer to determine variations in active ingredient content across random samples of granules from the same size classes. It was found that impeller design influenced the homogeneity of the granules and therefore can affect final product performance. The vari- ation in active ingredient content across granules of differing size was also investigated. The results show that small granules were more potent than larger granules,
文摘Some commonly used constructions and their design principles of centrifugal pump impeller with super low specific speed are introduced. The internal flow related to pump performance is analysed primarily.
基金Supported by National Natural Science Foundation of China(Grant No.51406148)National Science Technology Support Program of China(Grant No.2012BAA08B06)Postdoctoral Scientific Foundation of China(Grant No.2014M552444)
文摘Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression（SVR） metamodel is combined with the Monte Carlo simulation（MCS） method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.
文摘An impeller is the most important component affecting the performance of centrifugal fans. The flow in the impeller is very complicated, and the 3\|D viscous flow is difficult to simulate numerically. This paper presents a numerical method for simulating the flow in practical commercial impellers. The predictions are compared with experimentally measured fan performance results. The predicted total pressure and efficiency for two fan models, whose optimum designs were determined by this method, agree well with the measured data for the design flow rate. The results show that the aerodynamic and noise levels for these two models are excellent. The paper also presents several new ideas about the shape of the front plate and the blade flow pattern to improve the flow in an impeller channel. The practical simulation methodology and results developed here will be very useful to the fan industry in the future.
基金Fundação para a Ciência e Tecnologia(FCT-MCTES)Portugal,under contract UIDB/00102/2020Bluepharma,Coimbra,Portugal.The authors would like to acknowledge FCT for the financial support to João Gomes(CEECIND/01207/2018).
文摘Wet granulation is one of the most important agglomeration processes,and high-shear granulation(HSG)one of the most employed technologies in the pharmaceutical industry.The most critical process parameters of HSG are discussed in this work.The main concern in scaling up the wet granulation process is the differences between scales,which prevent the particles from having the same experience across all scales.The scale-up of wet granulation processes is commonly divided into two categories:engineering and attribute-based methods.An engineering-based scale-up approach is a strategy based on dimensional analysis and an attribute-based supported on the principles of“equifinality”,where process variables are adjusted to obtain equivalent granule attributes.This work presents the effect of different HSG process parameters on the scale-up,as well as the use of process analytical tools(PAT)and modelling strategies.The aim is to review applied scale-up approaches in HSG and discuss benefits and limitations.It is proven why the scale-up for oral solid pharmaceutical products is still considered a hot topic and a very challenging task for development and engineering teams.
